LAUSR

The prevalence and long‐term impact of T cell–mediated rejection (TCMR) is poorly defined in the modern era of tacrolimus/mycophenolate‐based maintenance therapy. This observational study evaluated 775 kidney transplant recipients with serial histology and correlated TCMR events with the risk of graft loss. After a ~30% incidence of a first Banff Borderline or greater TCMR detected on for‐cause (17%) or surveillance (13%) biopsies, persistent (37.4%) or subsequent (26.3%) TCMR occurred in 64% of recipients on follow‐up biopsies. Alloimmune risk categories based on the HLA‐DR/DQ single molecule eplet molecular mismatch correlated with the number of TCMR events (p = .002) and Banff TCMR grade (p = .007). Both a first and second TCMR event correlated with death‐censored and all‐cause graft loss when adjusted for baseline covariates and other significant time‐dependent covariates such as DGF and ABMR. Therefore, a substantial portion of kidney transplant recipients, especially those with intermediate and high HLA‐DR/DQ molecular mismatch scores, remain under‐immunosuppressed, which in turn identifies the need for novel agents that can more effectively prevent or treat TCMR.